Parent A, Hazrati L N
Centre de Recherche en Neurobiologie, Université Laval et Hôpital de l'Enfant-Jésus, Québec, Canada.
J Comp Neurol. 1994 Jun 8;344(2):305-20. doi: 10.1002/cne.903440211.
The pattern of arborization of the striatonigral fibers in the squirrel monkey (Saimiri sciureus) was studied with Phaseolus vulgaris-leucoagglutinin (PHA-L) and biocytin as anterograde tracers. Single, small injections of PHA-L or biocytin in either the caudate nucleus or the putamen give rise to at least four distinct, nonoverlapping but interconnected fiber plexuses that are distributed throughout the rostrocaudal extent of the substantia nigra pars reticulata (SNr) according to a strikingly precise and constant sequence. These plexuses, which comprise numerous fibers that closely entwine unlabeled dendrites of SNr neurons (woolly fibers), often lie at the base of dopaminergic cell columns of the substantia nigra pars compacta (SNc). Long and varicose fibers emerge dorsally from SNr plexuses and climb along the ventrally oriented dendrites of dopaminergic SNc neurons, as visualized with tyrosine hydroxylase immunohistochemistry. These fibers appear to contact en passant both dendrites and cell bodies of dopaminergic neurons belonging to the ventral tier of SNc. Anterograde double-labeling experiments involving small deposits of PHA-L and biocytin in adjacent areas of the caudate nucleus and the putamen reveal that neighboring striatonigral cell populations form two distinct sets of terminal plexuses that remain well segregated throughout SNr. Plexuses from the two sources interdigitate in some parts of SNr, but never intermix. Furthermore, the woolly fibers in these plexuses are composed exclusively of either PHA-L- or biocytin-labeled elements; none of them display both types of labeling. These results reveal that the striatonigral projection in primates is highly divergent and that the striatum has multiple representations at nigral levels. They also indicate that striatal information is conveyed to the substantia nigra in a highly ordered fashion through multiple segregated channels.
采用菜豆白细胞凝集素（PHA-L）和生物胞素作为顺行示踪剂，研究了松鼠猴（Saimiri sciureus）纹状体黑质纤维的分支模式。在尾状核或壳核中单次、小剂量注射PHA-L或生物胞素，会产生至少四个不同的、不重叠但相互连接的纤维丛，这些纤维丛根据一个非常精确和恒定的序列分布在黑质网状部（SNr）的整个前后范围内。这些纤维丛由许多紧密缠绕SNr神经元未标记树突的纤维组成（毛状纤维），它们通常位于黑质致密部（SNc）多巴胺能细胞柱的基部。如用酪氨酸羟化酶免疫组织化学观察到的，长而有曲张的纤维从SNr纤维丛背侧发出，并沿着多巴胺能SNc神经元腹侧的树突攀爬。这些纤维似乎在通过SNc腹侧层的多巴胺能神经元的树突和细胞体时形成过路接触。涉及在尾状核和壳核相邻区域小剂量注入PHA-L和生物胞素的顺行双重标记实验表明，相邻的纹状体黑质细胞群形成两组不同的终末纤维丛，它们在整个SNr中保持良好的分隔。来自两个来源的纤维丛在SNr的某些部分相互交错，但从不混合。此外，这些纤维丛中的毛状纤维仅由PHA-L或生物胞素标记的成分组成；它们中没有一个同时显示两种类型的标记。这些结果表明，灵长类动物的纹状体黑质投射高度分散，并且纹状体在黑质水平有多种表征。它们还表明，纹状体信息通过多个分离的通道以高度有序的方式传递到黑质。
